Numerical Simulation Study of Water Mist Cooling and Smoke Elimination in Tunnel Fire
Water mist system is widely used in tunnel fire because of its good smoke control effect.A numerical model of cooling and smoke abatement of water mist was proposed based on the mechanism of aerosol dynamics,and its effectiveness was verified by simulating the smoke suppression experiment of water mist in a narrow and long channel.In order to explore the influ-ence of particle size,spray cone angle and the distance between water mist and smoke vent on the cooling and smoke abatement effect,the model was further used to study the cooling and smoke abatement effect of water mist system in large-scale tunnel fire.The results show that the smaller the particle size of the droplets,the better the cooling and smoke abatement effect,and the smoke abatement efficiency is inversely proportional to the particle size.However,when the particle size is less than 100 μm,the smoke abatement efficiency decreases due to droplet evaporation;When the spray cone angle is 60°,the smoke abatement effect is the best.The increase or decrease of the spray cone angle will reduce the smoke abatement effect of the water mist sys-tem;When the distance between the water mist system and the smoke exhaust system is small,the smoke abatement effect will be weakened because the water mist droplets will be pulled out by the smoke exhaust system.Therefore,the greater the distance be-tween the two,the better the smoke abatement effect.
tunnel firewater mistnumerical simulationcooling and smoke abatementshading degree